1. Technical Field
The inventive arrangements relate generally to video systems and more particularly to video systems that record or play back digitally encoded video sequences.
2. Description of Related Art
Digital televisions (DTV) and high-definition televisions (HDTV) are gaining popularity in today's consumer electronics marketplace. Many purchasers of these types of televisions also buy digital video recorders or players, such as digital video disc (DVD) recorders or players, for purposes of viewing previously recorded programs or recording their favorite programs. Notably, the combination of a DTV (or an HDTV) and a digital video recorder or player can be an integral part of a home theater entertainment system.
A digital video recorder or player typically contains a Moving Pictures Expert Group (MPEG) decoder to decode the digitally encoded multimedia data that is stored on the discs that the recorder or player plays. If the digital video recorder or player is connected to a conventional (non-DTV or non-HDTV) television, the digitally encoded signal will be decoded by the digital video recorder or player's MPEG decoder before being displayed on the conventional television. Significantly, however, many DTVs contain their own MPEG decoders. As such, if a digital video recorder or player is connected to a DTV, the video signal read from the disc is remotely decoded by the DTVs decoder. This configuration can be referred to as a remote decoder arrangement.
There is, however, an important disadvantage in decoding digitally encoded signals with a remote DTV decoder. Namely, it is very difficult to perform trick modes in this type of arrangement. A trick mode can be any playback of video in which the playback is not done at normal speed or in a forward direction. Oftentimes, a trick mode involves skipping a number of pictures in a video signal such as during a fast motion trick mode. Skipping pictures in a video signal being transmitted to a remote decoder can actually increase the average bit rate of the signal. As the bandwidth between the digital video recorder or player and the DTV is limited, performing a fast motion trick mode may cause the signal to exceed the maximum bit rate limit of the transmission channel.
For instance, in an MPEG video signal, there are three separate types of digitally encoded pictures: intra (I) pictures, predictive (P) pictures and bidirectional predictive (B) pictures. As is known in the art, I and P pictures contain relatively large amounts of encoded data, at least with respect to B pictures. During a fast motion trick mode, the first pictures in a group of pictures (GOP) to be skipped are typically the B pictures. As the B pictures are skipped, however, the average amount of encoded data for the remaining pictures, or the average number of bits per picture, in the GOP increases. Such a drawback can lead to buffer overflow and the loss of pictures during the display of the trick mode video signal. Thus, a need exists for a method and system for performing a fast motion trick mode in a remote decoder arrangement without exceeding a maximum bit rate limit and without increasing system costs or complexity.